Gas measuring apparatus for detecting contaminants

ABSTRACT

Gas measuring apparatus is disclosed for detecting the presence of particles and other contaminants suspended in exhaust gases and the like. The apparatus includes a sensing system, preferably a photoelectric transceiver including a light source and detector mounted within a single housing, located out of the path of the gas being measured to prevent the contamination thereof. The sensing system disperses visible light (ultraviolet or infrared may be utilized) into the gas being measured such that the amount of light reflected and detected provides an output signal representative of the presence of particles and other contaminants suspended in the gas. An output system including an appropriate meter is responsive to the signal developed by the sensing system to provide a visible indication of the pollution of the gas. Various types of positioning frame assemblies may be utilized in conjunction with the basic system to extend its applicability to many common types of pollution expelling environments. Each of these embodiments may additionally be provided with a self-contained calibration unit for establishing predetermined levels for the measurement of pollutants.

ilnite tates Paint [72] Inventor Harry Einstein c/o Nebetco Engineering,1107 Chandler Ave., Roselle, NJ. 07203 [21] Appl. No. 774,871 [22] FiledNov. 12, 1968 [23] Continuation-impart of Ser. No. 681,517,

Nov. 8, 1967, Patent No. 3,541,336 [45] Patented Aug. 17, 1971 [54] GASMEASURING APP --.TUS FOR DETECTING CONTAMINANTS 23 Claims, 14 DrawingFigs.

[52] BS. Cl 250/218, 356/207, 250/234 [51] lnt.Cl ..G01n 21/26 [50]Field of Search 250/218, 83.3, 234, 226; 356/207, 208

[56] References Cited UNITED STATES PATENTS 616,760 12/1898 Baker356/233 1,785,393 12/1930 Sawford 356/207 1,976,672 10/1934 Peet 356/1852,082,252 6/1937 McDill. 356/208 2,363,473 11/1944 Ryder 250/2182,930,893 3/1960 Carpenter et a]. 250/833 3,317,730 5/1967 HilsumABSTRACT: Gas measuring apparatus is disclosed for detecting thepresence of particles and other contaminants suspended in exhaust gasesand the like. The apparatus includes a sensing system, preferably aphotoelectric transceiver including a light source and detector mountedwithin a single housing, located out of the path of the gas beingmeasured to prevent the contamination thereof. The sensing systemdisperses visible light (ultraviolet or infrared may be utilized) intothe gas being measured such that the amount of light reflected anddetected provides an output signal representative of the presence ofparticles and other contaminants suspended in the gas. An output systemincluding an appropriate meter is responsive to the signal developed bythe sensing system to provide a visible indication of the pollution ofthe gas. Various types of positioning frame assemblies may be utilizedin conjunction with the basic system to extend its applicability to manycommon types of pollution expelling environments. Each of theseembodiments may additionally be provided with mined levels for themeasurement of pollutants.

PATENTEI] we I 7 l9?! suit! 1 or 2 FIG. 1

INVENTOR.

HARRY EINSTEIN ATTORNEY PATENTEU AUBI 719?: 3 600 590 SHEEF 2 0F 2 FIG.11

BYXMW X AT TORNE Y GAS MEASURING APITUS FOR DETECTING CONTAMINANTS Thisinvention is a continuation in part of application Ser. No. 681,517filed Nov. 8, 1967, now U.S. Pat. No. 3,541,336 and entitled GasMonitoring Apparatus."

BACKGROUND OF THE INVENTION This invention relates to gas measuringapparatus for detecting the presence of particles and other contaminantssuspended in exhaust gases and the like, and more particularly relatesto such gas measuring apparatus which is relatively simple, andtherefore inexpensive. to manufacture, carefree in operation, portableand easily adaptable to a variety of common pollution expellingenvironments.

Air pollution has become one of the major problems of our day. Becauseof this, it has become increasingly more important to determine thesources of pollutants and to thereby learn how to control these sourcesto limit the contamination of the air we breath.

There have been many attempts to produce apparatus which can measurevarious sources of air pollution. One type of apparatus being utilizedoperates on chemical principles and produces an indication of the levelof air pollution by analyzing the reaction obtained when certainchemicals are combined with samples of the gas being analyzed. Anothertype of apparatus employs chromographic techniques to measure the changein electrical characteristics of various materials exposed to samples ofthe gas being analyzed, the change in electrical characteristics beingproportional to the influence of the contaminants in the sample.

However, the above described systems and indeed other prior artapparatus available for detecting contaminants in the air, suffer frommany disadvantages which will be shown, the instant inventioneffectively eliminates. Thus, prior art apparatus is technically complexand therefore costly to manufacture and maintain. Additionally, .thecomponents of such prior art apparatus are extremely fragile and subjectto breakage whereby the apparatus is frequently in its down state,subject to repair. Also, many if not all of the prior art systemsrequire that the contaminated gas come into intimate contact with thevarious sensing components thereof such that over extended periods ofuse, frequent service for cleaning the various components is required.The relatively complex systems of the prior art do not lend themselvesto being portable in nature. To the contrary, they must be accuratelyand firmly lodged at the site where the gas sample is taken. Finally,the systems of the prior art, are uniquely designed for a particularsampling embodiment, there being no basic system which can be simply andeasily adapted to measure exhaust gases and the like in the multiplicityof environments where such gases are generated. I

SUMMARY OF THE INVENTION In contradistinction, the instantinventionprovides gas measuring apparatus for detecting the presence of particlesand other contaminants suspended in exhaust gases and the like which isrelatively simple and therefore inexpensive and easy to manufacture. Asopposed to the fragile, difficult to calibrate, chemical and/orchromographic techniques utilized in the prior art, the gas measuringapparatus of the instant invention employs a simple, ruggedphotoelectric sensing system which detects the presence of contaminantsand particles by optically sensing the effect such particles orcontaminants have on a beam of light dispersed into the flow path of thegas being measured. In accordance with the invention, the photoelectricsensing system is positioned out of the path of the gas being measuredwhereby none of the components thereof will become soiled, therebysubstantially reducing service problems associated with cleaning thedevice.

As will be shown, the gas measuring apparatus of the instant inventionis extremely portable in nature and in fact includes a basic systemwhich can be simply and easily adapted to a variety of positioningsupport frames specifically designed to locate the photoelectric sensingsystem in operative relationship with respect to many different types ofpollution sources. Furthermore, and as a particularly advantageousfeature of the invention, each of the various embodiments of themeasuring apparatus may be provided with a self contained calibrationsystem whereby predetermined pollution levels can be easily established.

Accordingly, it is an object of the instant invention to provide gasmeasuring apparatus for detecting the presence of particles and othercontaminants suspended in the exhaust gases and the like.

Another object of the instant invention is to provide such gas measuringapparatus which includes a sensing system positionable out of the pathof the gas being measured and capable of providing an output signalrepresentative of the presence of contaminants in the gas; and an outputsystem responsive to the output signals of the sensing system forpresenting a recognizable signal indicative of the amount ofcontaminants in the gas.

Another object of the instant invention is to provide such a gasmeasuring apparatus wherein the sensing system thereof operates onphotoelectric principles to disperse a beam of radiation into the gasbeing monitored and to detect the amount of light reflected therefrom,the difference therebetween being attributable and proportional to theamount of particles and contaminants suspended in the gas beingmeasured.

Yet another object of the instant invention is to provide such a gasmeasuring apparatus wherein the photoelectric sensing system thereof ispreferably a transceiver combining a source of radiation and detector ina single housing, and wherein such transceiver is always positioned outof the path of the gas being measured to prevent contaminationtherefrom.

Another object of the instant invention is to provide such gas measuringapparatus employing a transceiver type of photoelectric sensing systemand which further employs a reflector similarly positioned out of thepath of the gas being measured to reflect light back toward thetransceiver.

Yet another object of the instant invention is to provide such gasmeasuring apparatus which can be quickly and easily provided withselectable filters of varying optical characteristics to easilyestablish predetermined reference levels of pollution.

Still another object of instant invention is to provide such gasmeasuring apparatus which is lightweight, portable, rugged, and easy tocalibrate.

Another object of the instant invention is to provide such gas measuringapparatus which can be easily provided with a variety of positioningassemblies which facilitates the location of the photoelectric sensingsystem thereof in operative relationship with a plurality of differenttypes of pollution expelling sources.

These and other objects of the instant invention may be had by referringto the following specification and drawings in which:

FIG. I shows a first embodiment of the gas measuring apparatus of theinstant invention;

FIG. la shows a perspective view of a funnelled basketlike structureuseful in accurately seating the apparatus of FIG. 1 in operativerelationship with respect to common exhaust pipes;

FIG. 2 is a view taken along the arrow 2-2 of FIG. 1;

FIG. 2a shows another embodiment of the plate used in the opticalcalibration unit by which the optical reference levels may beestablished by a series of openings of various diameters;

FIG. 3 is a view of the apparatus of FIG. 1 taken along the arrows 3-3thereof;

FIG. 4 is a plan view of a selectable calibration arrangement useful inthe embodiment of FIG. I and also adaptable to cooperate with variousother embodiments of the instant invention;

FIG. 5 is a plan view of an alternative embodiment of the instantinvention useful in measuring gases expelled by larger diameteredexhaust pipes and stacks than can be conveniently measured by theapparatus of FIG. 1;

FIG. 6 is a front view of the apparatus of FIG. 5;

FIG. 7 is a view of the apparatus of FIGS. 5 and 6 taken along thearrows 7-7 of FIG. 6;

FIG. 8 is a front view of yet another alternative embodiment of the gasmeasuring apparatus of the instant invention which is intended tomeasure gases flowing through large pipes and stacks;

FIG. 9 is a plan view of the apparatus of FIG. 8;

FIG. 10 is a plan view of yet another alternative embodiment of the gasmeasuring apparatus of the instant invention particularly adapted tomeasure gases expelled from exhaust pipes of automobiles and othervehicles;

FIG. 1 1 is a front view of the apparatus of FIG. 10; and

FIG. 12 is a view of the apparatus of FIGS. 10 and 1 1 taken along thearrows 12-12 of FIG. 10.

Turning to the drawings FIGS. 1-12 illustrate a plurality of differentembodiments of the gas measuring apparatus of the instant invention.Thus, in FIGS. 1-4, a first embodiment 10 of the instant invention isshown which is particularly adaptable to detect the presence ofparticles and other contaminants in the exhaust gases of relativelysmall pipes and stacks such as for example, the exhaust pipe of a dieseltractor-trailer, the gas expelling output end of which is customarilylocated approximately 10 to 15 ft. above the ground. FIGS. 5, 6 and 7illustrate an embodiment 12 of the gas measuring apparatus of theinstant invention which is particularly useful for measuring gasesexpelled from larger diametered exhaust pipes, stacks, and the likewherein the open expelling end of such devices is still reasonablyaccessible. FIGS. 8 and 9 illustrate a third embodiment 14 of the gasmeasuring apparatus of the instant invention which is useful formeasuring gas flowing in large pipes and stacks wherein the expellingopen end of such stacks are not accessible. Finally, FIGS. 1012illustrate a fourth embodiment 16 of the gas measuring apparatus of theinstant invention which is particularly useful for measuring exhaustgases of automobiles and the like, for instance at a motor vehicleinspection station. It should be noted that although the variousembodiments 10, 12, 14 and 16 are designed with specific applications inmind, they all share a common system, to be described immediately below,which is the heart of the gas measuring apparatus of the instantinvention. As noted previously, it is a particularly advantageousfeature of the in stant invention that this basic system can be simplyand easily converted to any one of the above described embodiments tofulfill a specific gas measuring function. In fact, once the basicsystem is described it will be apparent that various other specificallytailored embodiments employing the basic system of the invention can bedesigned to measure new pollution sources as they arise.

Turning now to FIG. 1, the common system of each of the variousembodiments will now be described, it being understood that the basicsystem to be described for the embodiment 10 is equally applicable tothe embodiments l2, l4 and 16 of the other figures. To make this pointexplicitly clear, like numerals will be used to identify similarcomponents of the various embodiments.

Thus the embodiment 10 includes a basic sensing system 18 for providingan output signal representative of the presence of particles and othercontaminants suspended in the gas 20 being measured. Preferably, thesensing system 18 employs photoelectric sensing principles and to thatend includes a source of radiation 20 which disperses a beam ofradiation 24 into the gas 20. Preferably, the source 20 emits whitelight but it is to be understood that if desired an ultraviolet orinfrared light source can be utilized for other contaminants normallyinvisible in the gas 20. The sensing system 18 further includes aradiation detector, preferably a common photo cell 26,

which senses the return of the radiation, indicated by the reversedarrows 28. The semitransparent mirror 22 directs some of the returnedradiation to the detector 26.

Partial or complete interruption of the beam, attributable to thequantity of contaminants and particles in the gas 20 is detected by thephoto cell 26 and produces an output signal which is transported bymeans of an expansible cable 32 to an output system 34 including anamplifier-controller 36 which converts the output signal to a useableelectric signal which can deflect an indicator 38 to provide arecognizable signal indicative of the amount of contaminants in the gas20. It is to be understood that the sensing system 18 and the outputsystem 34 including the amplifier-controller 36 and the indicator 38 arestandard articles of commerce and will not be described in any greaterdetail. Sufficient to note that a suitable source of such equipment isNebetco Engineering, 1107 Chandler Avenue-Roselle, NJ.

To be appreciated from the description thus far presented, is the factthat the entire sensing system 18 is located out of the path of the gas20 whereby it will not be exposed to the contamination flowing therein.This is to be contrasted from the prior art systems which require that asample of the contaminated air be drawn into the measuring apparatus.Also to beappreciated is the fact that the entire system 18 includingthe source of radiation 20 and the detector 26 is located in a singlehousing 40 such that the resulting system, conveniently called a lighttransceiver, is relatively simple and inexpensive to manufacture.(However, it is within the scope of the instant invention that thedetector 26 could, if desired, be located on the opposite side of thegas 20, out of its path, to prevent the contamination thereof.) If atransceiver system is utilized, a reflector 42 is located at theopposite side of the gas 20 out of its path to prevent any accumulationof dirt and particles thereon.

When testing for the presence of black, light-absorbing particles, it isthe amount of radiation which is not absorbed by these particles whichis reflected by the reflector 42 and detected by the photocell 26 toprovide an indication of the quantity of contamination in the gas. Ifwhite particles are to be sensed, the reflector 42 is covered by anonreflective cover, (not shown) such that only the amount of lightwhich is reflected from the white particles themselves will be detectedby the photocell 26 to provide the indication of pollution. When sensingwhite particles, however, a different transceiver 18 would be utilized,one having a greater sensitivity and stronger light source 20.

To calibrate the measuring apparatus of the instant invention it ismerely necessary to obtain a reading on the indicator 38 when theradiation is traversing ambient air which does not include the pollutioncontaining gas 20. The reading obtained thereby becomes the referencefrom which the actual pollution measuring indications can be compared.Preferably, a know 44 is rotatable to locate the indicator 38 at zeropoint on the scale therebeneath when testing the ambient atmosphere.

Another common feature applicable to all of the embodiments 10, 12, 14and 16 is the utilization of a self-contained optical calibration unit46 comprising an elongated plate 48 having a plurality of apertures 50,52 and 54 therein. Aperture 52 is left open while apertures 50 and 54are masked with filters having preselected optical characteristics toestablish predetermined reference levels of pollution when these filtersare located in the path of the radiation generated by the source 20. Asbest seen in FIG. 2, the plate 48 is slidably mounted as for example bymeans of bearings 56 secured on an end plate 58 to be described ingreater detail, such that the plate 48 can be slid to locate either theopen aperture 52 or any one of the filters 50 and 54 in the path of thebeam 24, 28. It is noted that although the calibration unit 46 has beenshown in the drawing as applied only to the embodiments 10 and 12, sucha filter arrangement may be equally applied in front of the sensingsystem 18 of the embodiments 14 and 16 of FIGS. 8 and 10 respectively.In a simpler, more preferred embodiment, the optical reference levelsmay be established by a series of openings of various diameters such asshown at 51, 53, and 55 in FIG. 2-A. The result will be similar to thevarious diaphragm openings of a camera system and will permit the systemto be operated with preselected amounts of light. With such anembodiment the plate 48' of FIG. 2A is provided with notches 57 and theend plate 58 provided with a spring biased detent means 59 to accuratelylocate the respective aperture in proper relationship with respect tothe source.

The one final element found in all of the various embodiments of theinstant invention may be broadly designated positioning apparatus 60 inthe various drawings for accurately locating the sensing system 18 inoperative relationship with respect to the gas to be measured and foradditionally supporting the reflector 42 in proper alignment with thebeam 24, 28.

Thus the embodiment of FIG. 1, the positioning means 60 includes alongitudinally extending frame 62 comprised of a plurality of rigidwirelike struts 64 parallelly disposed about a pair of end plate members58 and 66, the plate 58 being secured to the housing 40. Although notshown it is, of course, obvious that the end plate 58 is provided with acentral aperture through which the beam 24, 28 may pass. The struts 64are spaced close enough that any two adjacent struts define a planersurface which can be rested upon the top of a small pipe or stack whichis expelling the gas to be measured. Additionally, the struts 64 mayinclude outstanding projections 68 which function as limit stops todefine the longitudinal section of the frame 62 within which the end ofthe pipe being measured should be located.

Since many exhaust pipes, stacks and the like terminate in other thanregular cylindrical openings, and since even many cylindricallyterminated exhaust pipes decay into jagged terminations, the positioningassembly 60 of the embodiment 10 of FIG. ll may further include aninverted funnellike basket member 70 (FIG. la) which includes hooklikeprojections 72 by which the member 70 can be hung from any of thevarious struts 64, again within the confines established by theprojections 68. With the aid of the basketlike member 70, hanging fromthe frame 62, it is a relatively simple matter to locate the gasmeasuring apparatus over the end of any size or shaped pipe or stack. Ofcourse a more conventional funnel structure fabricated from sheet metalor plastic can be utilized. The entire apparatus including the sensingsystem 18 and the positioning assembly 60 is carried at one end 74 of anelongated post 76, the opposite, end 78 of which can be convenientlyhand grasped by the user. The post may consist of extensible orcollapsible tubes if desired. The housing 40 is preferably pivotallyconnected to the end 74 by means of a rotatable arrangement 80.Furthermore, the output system 34 is slidably positionable on the rod 76by means of a circular band 82 which circumscribes the post 76 andincludes a hand knob 84 therethrough which can be manually tightened tosecure the output system at any convenient point along the post. Theexpansible cable 32 is useful in the situation where the sensing system34 is slid relatively far down the end 78 of a lengthy post 76. I

Turning to FIGS. 5-7, the embodiment 12 of the gas measuring apparatusof the instant invention is as noted previously, very similar to theembodiment 10 of FIGS. I4 and therefore like numerals have been used todesignate like elements. The primary difference is that the positioningassembly 60 of the embodiment 12 comprises simply an elongated supportrod 86 secured at one end to the end plate member 58 and at its oppositeend provided with a transverse flange 88 which carries the reflector 42.

As suggested in FIG. 6, the embodiment 12, like the embodiment 10 ofFIG. ll, is preferably hand-held by means of the post 76 aboverelatively larger diametered stacks and the like which do not requirethe frame 62 of FIG. 1 to properly locate the sensing system 18 withrespect to the gas monitored. Of course, if desired an invertedbasketlike arrangement similar to the element 70 of FIG. 1a could besuspended from the support rod 86 to facilitate the housing process.

Turning to FIGS. 8 and 9, there is shown the third embodiment 14 of themeasuring apparatus of the instant invention. In this embodiment, thepositioning means 60 comprises an arcuate support member 90 whichpartially circumvents a pipe or stack 92. This arrangement isparticularly useful for tall stacks where it is impossible to reach theupper exit point thereof. Additionally, this embodiment being a morepermanent device, lends itself to continuous measurement or monitoring.

One end 94 of the arcuate member 90 carries the sensing system 18 bymeans of an L" shaped support 96. The end 94 is additionally secured toa vertical rod 98 which is freely rotatable within apertures provided ina frame 100 secured to the stack 92 by bands 102 thereabout. Theopposite end 104 of the arcuate member 90 carries the reflector 42. Whenfunctioning to monitor the gas flowing through the stack 92, the arcuatemember 90 rests against the stack 92, with adjustment or alignment ofthe optical components being made by adjustable stop 106. The systemswings open to permit measurement in ambient air. Reference slidefilters, such as shown in FIG. 2 and 2A, are used in the ambient airposition. Although not clearly shown in FIGS. 8 and 9, it is to beunderstood that when using the embodiment 14, suitable apertures must beprovided in the stack 92 to permit the passage of the radiation beamtherethrough.

Turning to FIGS. 10-12, there is shown the last embodiment 16 of the gasmonitoring apparatus of the instant invention in which embodiment thepositioning assembly 16 actually comprises and enclosed chamber 108 onthe exterior of which are supported the sensing system 18 and thereflector 42. The chamber includes an inlet port 110 and an exit port112 between which is established a flow path 114 for the gas beingmeasured. Preferably an exhaust fan 116 is utilized to draw the gas outthe port 112. A baffle plate 118 is provided adjacent the reflector 42such that any laminar flow of the gas ll 14 which might disburselaterally-out of the central flow path will avoid contaminating thereflector 42 as suggested by the arrows 120.

Secured about the inlet port 1 10 is a flexible hollow conduit 122 whichcan easily be secured on to the exhaust pipes of an tomobiles, trucks,and other vehicles. The embodiment 16 could conveniently be utilized inmotor vehicle inspection stations to quickly provide an indication ofthe effectiveness of the exhaust system of vehicles. If the unit isbeing operated within a confined area, an outlet tube 124 is preferablyconnected at one end to the exit port 112 and its opposite end (notshown) to the outside of the station such that the operators would notbe exposed to excessive amounts of carbon monoxide.

Thus there has been described gas measuring apparatus which in aplurality of different embodiments, employs photoelectric sensing meansto detect the presence of particles and other contaminants in the gasbeing measured. All of the embodiments possess common features such aslocating the photoelectric sensingsystem out of the path of the gas toprevent contamination thereof and each include simple positioning systemwhereby the apparatus can be properly located with respect to the gasbeing measured. All of the embodiments are simple, rugged, lightweight,portable and require little if any servicing.

Although this invention has been described with respect to its preferredembodiments, it should be understood that many variations andmodifications will now be obvious to those skilled in the art, and it ispreferred, therefore, that the scope of the invention be limited, not bythe specific disclosure herein, only by the appended claims.

I claim:

ll. Gas measuring apparatus for detecting the presence of particles andother contaminants suspended in exhaust gases and the like comprising:

sensing means positionable out of the path of the gas being measured,said sensing means being capable of providing an output signalrepresentative of the presence of particles and other contaminantssuspended in said gas;

output means responsive to said output signal of said sensing means forconverting said output signal into a recognizable signal indicative ofthe amount of contaminants in said gas;

wherein said sensing means comprises a source of radiation fordispersing radiation into said gas being measured, and radiationsensitive detector means responsive to the magnitude of radiationreturned from said gas for producing said output signal;

wherein said source of radiation and said radiation sensitive detectormeans are both mounted within a single housing positioned at preselectedlocation adjacent to and on one side of the gas being measured;

further including reflector means supported at a second preselectedlocation out of the path of the gas being measured, said secondpreselected location being chosen to reflect radiation generated by saidradiation source back toward said radiation sensitive detector means inradiation paths which pass through said gas being measured, whereby theamount of radiation which is sensed by said detector means will differfrom the amount of radiation generated by said radiation source by anamount which is attributable to absorption by particles and othercontaminants in said gas; and

wherein said reflector means is supported at its second preselectedlocation by support means secured at one end to said single housing andat its opposite end to said reflector means.

2. The gas measuring apparatus of claim 1 and further including covermeans for selectively making said reflector means totally nonreflectivewhereby said detector means will detect radiation reflected by particlesand other contaminants in said gas.

3. The gas measuring apparatus of claim 2 wherein said sensing means islocated at a preselected location adjacent to but out of the path of thegas being measured.

4. The gas measuring apparatus of claim 1 and further includingcalibration means selectively positionable in the path of said radiationfor establishing predetermined reference levels of pollution.

5. The gas measuring apparatus of claim 4 wherein said calibration meanscomprises a plate member having at least two apertures therein, one ofsaid apertures being open, one of said apertures being masked by afilter of chosen optical characteristics, said plate member beingslidably mounted with respect to said housing such that either of saidapertures may be located in the path of radiation.

6. The gas measuring apparatus of claim 4 wherein said calibration meanscomprises a plate member having a plurality of apertures of preselecteddiameter relationships with respect to one another, said plate memberbeing movably mounted with respect to said sensing means such that anyone of said apertures may be located in the path of radiation.

7. Gas measuring apparatus for detecting the presence of particles andother contaminants suspended in exhaust gases and the like comprising:

sensing means positionable out of the path of the gas being measured,said sensing means being capable of providing an output signalrepresentative of the presence of particles and other contaminantssuspended in said gas;

output means responsive to said output signal of said sensing means forconverting said output signal into a recognizable signal indicative ofthe amount of contaminants in said gas;

wherein said sensing means comprises a source of radiation fordispersing radiation into said gas being measured, and radiationsensitive detector means responsive to the magnitude of radiationreturned from said gas for producing said output signal;

wherein said source of radiation and said radiation sensitive detectormeans are both mounted with a single housing positioned at a preselectedlocation adjacent to and on one side of the gas being measured; and

wherein said positioning means includes a longitudinally extending frameincluding a plurality of struts radially disposed about a pair of endplate members.

8. The gas measuring apparatus of claim 7 and further includingreflector means for reflecting radiation generated by said source ofradiation back toward said detector means, said reflector means beingsupported on said second of said pair of end plate members out of thepath of the gas being measured.

9. The gas measuring apparatus of claim 7 wherein said positioning meansfurther includes locating means secured to preselected ones of saidstruts for firmly locating said frame above a vessel dispersing the gasto be measured.

10. The gas measuring apparatus of claim 9 wherein said locating meanscomprises an inverted funnellike member slidably disposed on preselectedones of said funnellike member thereon.

11. Gas measuring apparatus for detecting the presence of particles andother contaminants suspended in exhaust gases and the like comprising:

sensing means positionable out of the path of the gas being measured,said sensing means being capable of providing an output signalrepresentative of the presence of particles and other contaminantssuspended in said gas;

output means responsive to said output signal of said sensing means forconverting said output signal into a recognizable signal indicative ofthe amount of contaminants in said gas;

wherein said sensing means comprises a source of radiation fordispersing radiation into said gas being measured, and radiationsensitive detector means responsive to the magnitude of radiationreturned from said gas for producing said output signal;

wherein said source of radiation and said radiation sensitive detectormeans are both mounted within a single housing positioned at apreselected location adjacent to and on one side of the gas beingmeasured;

further including positioning means connected to said sensing means foraccurately locating said sensing means in operative relationship withrespect to the gas to be measured; and

further including positioning means connected to said sensing means foraccurately locating said sensing means in operative relationship withrespect to the gas to be measured; and

wherein said positioning means includes an arcuate support membercarrying said sensing means out of the path of the gas being measured,said arcuate support member having fastening means for pivotallysecuring said support member to the exterior of a stack within which thegas to be measured is flowing, said stack being provided with aperturemeans aligned with said sensing means to permit the introduction of saidradiation into said stack.

12. The gas measuring apparatus of claim 11 further including reflectormeans for reflecting radiation generated by said source of radiationback toward said detector means, said reflector means being supported ona second end of said arcuate support member out of the path of the gasbeing measured, said stack being provided with a second aperture alignedwith said reflector means.

13. The gas measuring apparatus of claim 12 and further includingcalibration means selectively positionable in the path of said radiationfor establishing predetermined reference levels of pollution.

14. The gas measuring apparatus of claim 13 wherein said calibrationmeans comprises a plate member having at least two apertures therein,one of said apertures being open, one said apertures being masked by afilter of chosen optical characteristics, said plate member beingslidably mounted with respect to said sensing means such that either ofsaid apertures may be located in the path of radiation.

15. The gas measuring apparatus for detecting the presence of particlesand other contaminants suspended in exhaust gases and the likecomprising:

sensing means positionable out of the path of the gas being measured,said sensing means being capable of providing an output signalrepresentative of the presence of particles and other contaminantssuspended in said gas;

wherein said sensing means comprises a source of radiation fordispersing radiation into said gas being measured, and radiationsensitive detector means responsive to the magnitude of radiationreturned from said gas for producing said output signal;

wherein said source of radiation and said radiation sensitive detectormeans are both mounted within a single housing positioned at apreselected location adjacent to and on one side of the gas beingmeasured;

further including positioning means connected to said sensing means foraccurately locating said sensing means in operative relationship withrespect to the gas to be measured; and

wherein said positioning means, includes an enclosed chamber having aninput port for the entrance of the gas to be measured and an exit portfor the exit of the gas being measured to define a flow path of said gastherebetween, said sensing means being mounted on said chamber todisperse radiation into said flow path.

16. The gas measuring apparatus of claim and further including flexibleconduit means connected to said input port for facilitating themeasuring of gases generated at locations remote from said chamber.

' 17. The gas measuring apparatus of claim 15 and further includingexhaust fan means located within said chamber for drawing said gas outof said chamber through said exit port.

18. The gas measuring apparatus of claim 15 wherein said single housingis supported on the exterior of said enclosed chamber, said chamberbeing provided with an aperture aligned with said sensing means topermit the entry of said radiation into said chamber.

19. The gas measuring apparatus of claim 18 and further includingreflecting means for reflecting radiation generated by said source ofradiation back toward said detector means, said reflector means beinglocated outside said chamber.

20. The gas measuring apparatus of claim 19 and further including bafflemeans located adjacent said reflector means for preventing said gas fromcontacting said reflector means.

21. The gas measuring apparatus of claim 15 and further includingcalibration means selectively positionable in the path of said radiationfor establishing predetermined reference levels of pollution.

22. The gas measuring apparatus of claim 21 wherein said filter meanscomprises a plate member having at least two apertures therein, one ofsaid apertures being open, one of said apertures being masked by afilter of chosen optical characteristics, said plate member beingslidably mounted with respect to said sensing means such that either ofsaid apertures may be located in the path of radiation.

23. The gas measuring apparatus of claim 7 wherein said struts includeoutstanding projection means for defining a section of said frame withinwhich said gas is to flow.

2. The gas measuring apparatus of claim 1 and further including cover means for selectively making said reflector means totally nonreflective whereby said detector means will detect radiation reflected by particles and other contaminants in said gas.
 3. The gas measuring apparatus of claim 2 wherein said sensing means is located at a preselected location adjacent to but out of the path of the gas being measured.
 4. The gas measuring apparatus of claim 1 and further including calibration means selectively positionable in the path of said radiation for establishing predetermined reference levels of pollution.
 5. The gas measuring apparatus of claim 4 wherein said calibration means comprises a plate member having at least two apertures therein, one of said apertures being open, one of said apertures being masked by a filter of chosen optical characteristics, said plate member being slidably mounted with respect to said housing such that either of said apertures may be located in the path of radiation.
 6. The gas measuring apparatus of claim 4 wherein said calibration means comprises a plate member having a plurality of apertures of preselected diameter relationships with respect to one another, said plate member being movably mounted with respect to said sensing means such that any one of said apertures may be located in the path of radiation.
 7. Gas measuring apparatus for detecting the presence of particles and other contaminants suspended in exhaust gases and the like comprising: sensing means positionable out of the path of the gas being measured, said sensing means being capable of providing an output signal representative of the presence of particles and other contaminants suspended in said gas; output means responsive to said output signal of said sensing means for converting said output signal into a recognizable signal indicative of the amount of contaminants in said gas; wherein said sensing means comprises a source of radiation for dispersing radiation into said gas being measured, and radiation sensitive detector means responsive to the magnitude of radiation returned from said gas for producing said output signal; wherein said source of radiation and said radiation sensitive detector means are both mounted with a single housing positioned at a preselected location adjacent to and on one side of the gas being measured; and wherein said positioning means includes a longitudinally extending frame including a plurality of struts radially disposed about a pair of end plate members.
 8. The gas measuring apparatus of claim 7 and further including reflector means for reflecting radiation generated by said source of radiation back toward said detector means, said reflector means being supported on said second of said pair of end plate members out of the path of the gas being measured.
 9. The gas measuring apparatus of claim 7 wherein said positioning means further includes locating means secured to preselected ones of said struts for firmly locating said frame above a vessel dispersing the gas to be measured.
 10. The gas measuring apparatus of claim 9 wherein said locating means comprises an inverted funnellike member slidably disposed on preselected ones of said funnellike member thereon.
 11. Gas measuring apparatus for detecting the presence of particles and other contaminants suspended in exhaust gases and the like comprising: sensing means positionable out of the path of the gas being measured, said sensing means being capable of providing an output signal representative of the presence of particles and other contaminants suspended in said gas; output means responsive to said output signal of said sensing means for converting said output signal into a recognizable signal indicative of the amount of contaminants in said gas; wherein said sensing means comprises a source of radiation for dispersing radiation into said gas being measured, and radiation sensitive detector means responsivE to the magnitude of radiation returned from said gas for producing said output signal; wherein said source of radiation and said radiation sensitive detector means are both mounted within a single housing positioned at a preselected location adjacent to and on one side of the gas being measured; further including positioning means connected to said sensing means for accurately locating said sensing means in operative relationship with respect to the gas to be measured; and further including positioning means connected to said sensing means for accurately locating said sensing means in operative relationship with respect to the gas to be measured; and wherein said positioning means includes an arcuate support member carrying said sensing means out of the path of the gas being measured, said arcuate support member having fastening means for pivotally securing said support member to the exterior of a stack within which the gas to be measured is flowing, said stack being provided with aperture means aligned with said sensing means to permit the introduction of said radiation into said stack.
 12. The gas measuring apparatus of claim 11 further including reflector means for reflecting radiation generated by said source of radiation back toward said detector means, said reflector means being supported on a second end of said arcuate support member out of the path of the gas being measured, said stack being provided with a second aperture aligned with said reflector means.
 13. The gas measuring apparatus of claim 12 and further including calibration means selectively positionable in the path of said radiation for establishing predetermined reference levels of pollution.
 14. The gas measuring apparatus of claim 13 wherein said calibration means comprises a plate member having at least two apertures therein, one of said apertures being open, one said apertures being masked by a filter of chosen optical characteristics, said plate member being slidably mounted with respect to said sensing means such that either of said apertures may be located in the path of radiation.
 15. The gas measuring apparatus for detecting the presence of particles and other contaminants suspended in exhaust gases and the like comprising: sensing means positionable out of the path of the gas being measured, said sensing means being capable of providing an output signal representative of the presence of particles and other contaminants suspended in said gas; wherein said sensing means comprises a source of radiation for dispersing radiation into said gas being measured, and radiation sensitive detector means responsive to the magnitude of radiation returned from said gas for producing said output signal; wherein said source of radiation and said radiation sensitive detector means are both mounted within a single housing positioned at a preselected location adjacent to and on one side of the gas being measured; further including positioning means connected to said sensing means for accurately locating said sensing means in operative relationship with respect to the gas to be measured; and wherein said positioning means, includes an enclosed chamber having an input port for the entrance of the gas to be measured and an exit port for the exit of the gas being measured to define a flow path of said gas therebetween, said sensing means being mounted on said chamber to disperse radiation into said flow path.
 16. The gas measuring apparatus of claim 15 and further including flexible conduit means connected to said input port for facilitating the measuring of gases generated at locations remote from said chamber.
 17. The gas measuring apparatus of claim 15 and further including exhaust fan means located within said chamber for drawing said gas out of said chamber through said exit port.
 18. The gas measuring apparatus of claim 15 wherein said single housing is supported on the exterior of said enclosed chamber, said chamber being provided with an aperture aligNed with said sensing means to permit the entry of said radiation into said chamber.
 19. The gas measuring apparatus of claim 18 and further including reflecting means for reflecting radiation generated by said source of radiation back toward said detector means, said reflector means being located outside said chamber.
 20. The gas measuring apparatus of claim 19 and further including baffle means located adjacent said reflector means for preventing said gas from contacting said reflector means.
 21. The gas measuring apparatus of claim 15 and further including calibration means selectively positionable in the path of said radiation for establishing predetermined reference levels of pollution.
 22. The gas measuring apparatus of claim 21 wherein said filter means comprises a plate member having at least two apertures therein, one of said apertures being open, one of said apertures being masked by a filter of chosen optical characteristics, said plate member being slidably mounted with respect to said sensing means such that either of said apertures may be located in the path of radiation.
 23. The gas measuring apparatus of claim 7 wherein said struts include outstanding projection means for defining a section of said frame within which said gas is to flow. 